A Phase 3 interventional study of Clemizole HCl and Placebo in Lennox Gastaut Syndrome, sponsored by Epygenix. Recruiting at 71 sites in 10 countries. Open to participants aged 2 Years to 55 Years. Per ClinicalTrials.gov, last updated 2026-10-09.
Sponsored by Epygenix · Phase 3, Interventional, and Treatment
This is a multicenter, Phase 3, randomized, double-blind, placebo-controlled study designed to evaluate the efficacy and safety of clemizole HCL (EPX-100) as adjunctive therapy in children and adult participants with Lennox-Gastaut syndrome (LGS).
This is a multicenter, Phase 3, randomized, double-blind, placebo-controlled study designed to evaluate the efficacy and safety of clemizole HCl as adjunctive therapy in children and adult participants with LGS.
The study will consist of an Observational Period, a Double-Blind (DB) Period, and an optional Open-Label Extension (OLE) Period.
68 studies on the registry are indexed under Lennox Gastaut Syndrome; 14 are open to participants now.
This study's planned enrollment of 260 is above the median of 40 across 49 interventional studies indexed under Lennox Gastaut Syndrome.
Browse Lennox Gastaut Syndrome studies →Epygenix is the lead sponsor of 5 studies on the registry; 3 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Key Inclusion Criteria:
Diagnosis of LGS, including:
Key Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will receive their first dose of study drug following randomization.
Drug: Placebo
Participants will receive their first dose of study drug following randomization.
Drug: Clemizole HCl
Eligible participants who complete the DB Period will have the option to continue in the OLE Period, during which they will receive clemizole HCl for up to 3 years.
Drug: Clemizole HCl
Clemizole HCl will be administered as an oral solution.
Also known as: EPX-100
Placebo will be administered as an oral solution.
Percent Change in CMMS-28
Percent change in CMMS-28 from the Baseline Period through the end of the DB Period
Time frame: From Baseline Period up to 16 weeks
Proportion of Participants with ≥50% Reduction in CMMS-28
Proportion of participants with ≥50% reduction in CMMS-28 from the Baseline Period through the end of the DB Period
Time frame: From Baseline Period up to 16 weeks
Percent Change in CMMS-28 Seizure-free Days
Percent change in CMMS-28 seizure-free days from the Baseline Period through the end of the DB Period
Time frame: From Baseline Period up to 16 weeks
Clinical Global Impression of Change (CGI-C) Score
CGI-C score at the end of the DB Period
Time frame: Week 16
Caregiver Global Impression of Change (CaGI-C) Score
CaGI-C score at the end of the DB Period
Time frame: Week 16
Caregiver Global Impression of Change in Seizure Intensity/Duration (CaGI-CSID) Score
CaGI-CSID score at the end of the DB Period
Time frame: Week 16
Change in Quality of Life Inventory (QI)-Disability Score
Change in QI-disability score from Baseline to the end of the DB Period
Time frame: From Baseline Period up to 16 weeks
Percent Change per 28 Days in the Number of Seizure Free Days
Percent change per 28 days in the number of seizure-free days (based on all seizure types) from the Baseline Period through the end of the DB Period
Time frame: From Baseline Period up to 16 weeks
Percent Change in CMMS-28
Percent change in CMMS-28 from the Baseline Period through the end of the DB Maintenance Phase only
Time frame: From Baseline Period up to 12 weeks
Proportion of Participants with ≥50% Reduction in CMMS-28
Proportion of participants with ≥50% reduction in CMMS-28 from the Baseline Period through the end of the DB Maintenance Phase only
Time frame: From Baseline Period up to 12 weeks
Incidence of Treatment-Emergent Adverse Events (TEAEs)
Incidence of TEAEs will be compared among the treatment groups
Time frame: From the first dose administration of study drug up to end of the study, approximately up to 172 weeks
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Plan to share: No
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Studies of the drug tested here: Clemizole hydrochloride
Epygenix